High Surface Activity Research Articles

Effect of Different Molten Salts on Structure and Water Splitting Performance of Al-Doped Fillet Polyhedral SrTiO3.

Strontium titanium (SrTiO3) is a promising photocatalyst, but enhancing the separation, migration, and utilization of photocarriers, requires SrTiO3 with exposed anisotropic facets and minimal defect density. Here, we used NaCl and SrCl2 as fluxes to synthesize fillet polyhedral SrTiO3 particles, with Al3+ selectively adsorbed as the morphology regulator on high-energy crystal facets. Notably, Al-doped SrTiO3 synthesized in SrCl2 exhibits regular polyhedral morphology with {100}, {110}, and high-index {112} facets, showing high surface activity, low internal defect density, and superior photocatalytic performance. The excellent performance is attributed to the spatial separation of photocarriers on different crystal facets. In situ photodeposition experiments confirmed that photogenerated electrons were concentrated on the {100} facets, while holes were concentrated on the {110} and {112} facets, effectively impeding recombination. After loading RhCrOx/CoOx, Al-doped SrTiO3 synthesized in SrCl2 achieves a hydrogen evolution rate of 255µmol h-1, 64 times higher than that of Al-doped SrTiO3 synthesized in NaCl. Additionally, increasing amounts of cocatalysts further enhances the photocatalytic performance, with the average hydrogen evolution rate of SrTiO3 reaching 319µmol h⁻¹, an apparent quantum yield of 3.5% at 365nm, and a solar-to- hydrogen value of 0.181%. This discovery offers new insights into designing efficient photocatalysts for hydrogen production.

Enhancing electrochemical performance of Co3O4/ZnO composite nanostructures through interface engineering for oxygen evolution reaction

Co3O4/ZnO composite nanostructures were successfully synthesized via a simple hydrothermal method followed by air-based calcination at 500°C. The resulting hexagonal heterostructure composite with a large interfacial area demonstrates exceptional oxygen evolution electrocatalytic activity with an overpotential of 288 mV at 10 mA cm-², and a low Tafel slope (80 mV dec⁻¹). This enhanced activity is attributed to the Co3O4/ZnO p-n junction, where ZnO (an n-type semiconductor) and Co3O4 (a p-type semiconductor) meet, which is crucial for boosting catalytic activity. This interface enables swift electron movement between the two materials, resulting in better charge separation and decreased charge recombination. Additionally, the high active surface area, confirmed by cyclic voltammetry measurements, further contributes to the improved OER performance. The well-defined interfaces within the Co3O4/ZnO heterostructures provide abundant active sites, facilitating efficient charge transfer kinetics. This research highlights the potential of composite heterostructures as promising electrocatalysts for water-splitting applications.

Synergistic lanthanum /nitrogen co-modified carbon dots as steel corrosion inhibitor

Carbon dots have significantly contributed to corrosion resistance due to their varied physical and chemical properties, excellent biocompatibility, and high surface activity. Therefore, designing and developing high-performance carbon dot inhibitors is of great significance. The study successfully synthesized lanthanum and nitrogen co-modified carbon dots (La/N-CDs), which function as a green and effective corrosion inhibitor. It was found that the La/N-CDs inhibitor presented a nanostructure with size of 3–9 nm. Electrochemical experiments, such as Tafel plots and EIS, showed that the presence of La/N-CDs effectively suppressed metal corrosion in a chloride-containing corrosion solution. In a 3 wt% NaCl solution, 400 mg/L La15 %/N-CDs exhibited the best corrosion inhibition performance, with an impedance modulus of 2165.33 Ω cm² and an inhibition efficiency reaching as high as 93.07 %, while the surface roughness of the steel and the corrosion rate was also minimized. This might be explained by the formation of an adsorption layer by La/N-CDs on the metal surface, a phenomenon confirmed by Langmuir isotherm and XPS investigations. These findings confirmed that La/N-CDs could form a protective film on the metal surface, significantly improving its corrosion resistance and extending its service life in corrosion environment. The study’s findings offered insights and a conceptual structure for enhancing corrosion inhibitors using carbon dots that were augmented with rare earth elements.

Does the active surface area determine the activity of silica supported nickel catalysts in CO2 methanation reaction?

Two series of silica supported catalysts with comparable nickel contents varying from 2.5 to 20 wt.% were prepared by wet impregnation method in the absence and presence of citric acid in the impregnation solution. Temperature-programmed reduction, X-ray diffraction and electron microscopy studies indicated changes of reducibility of nickel oxide species in the corresponding catalysts and formation of nickel nanoparticles of different size and morphology. A gradual increase in the performance of catalysts in the CO2 methanation reaction was observed with increasing Ni loading. The application of a modified impregnation method led to a reduction in the size of the nickel crystallites, which increased the active surface area of the catalysts, improving their activity and selectivity towards methane at low temperatures, as well as their stability at high temperatures. It was shown that the high active surface area of silica-supported nickel catalysts, due to the presence of small crystallites, is a key factor in increasing their activity. However, other catalyst properties may also play an important role. Hydrogen temperature-programmed desorption and in-situ DRIFTS adsorption/desorption of CO, CO2 and CO2 hydrogenation reaction studies indicated that modification of the method of catalyst synthesis led to changes in the surface properties of the catalysts, affecting the way CO2 and H2 activation and the transformation of resulted intermediate species to the final reaction products.

Se-Doped CoS2@MoS2 Heterostructures on Multiwalled Carbon Nanotubes as Efficient Bifunctional Electrocatalysts for Alkaline Overall Water Splitting.

The use of efficient and affordable non-precious metal catalysts for hydrogen and oxygen evolution reactions is vital for replacing and widely implementing new energy sources. Nevertheless, improving the catalytic performance of these non-precious-metal bifunctional electrocatalysts continues to be a major challenge. In this article, an optimized Se-incorporated bulk CoS2@MoS2 heterostructure grown on the surface of carbon nanotubes is reported. The resulting Se-CoS2@MoS2/CNTs exhibit robust bifunctional electrocatalytic performance, with low overpotentials of 85 and 240mV @ 10 mA·cm-2 for HER and OER, respectively. The materials exhibit superior long-term stability of over 145h, surpassing most electrocatalysts of similar type. This enhanced performance is attributed to the synergistic effect at the interface between the MoS2 and CoS2 phases, abundant active sites, and high active surface area, which collectively improves the electron-transfer efficiency during the reaction process. Furthermore, the incorporation of the amorphous state of Se into the heterostructure yields a change in the crystallinity of the heterostructure in the electronic structure, which optimizes the adsorption and activation energy barriers of the catalytic intermediate. This study thus presents a promising approach to regulating anion doping in bifunctional electrocatalysts.

High surface density of Mn-N sites in atomically dispersed Mn catalyst for effective CO2 electroreduction

Electrocatalytic CO2 reduction to chemical fuels driven by renewable energy provides a highly promising route to fabricate the circular economy. However, the high overpotential and competitive side reactions severely hinder the industrial application of this process. Here we prepare the atomically dispersed Mn catalyst with high surface density of Mn-N sites via carbon protection and pyrolysis strategies, which exhibits a maximum of 90 % CO faradaic efficiency and the low overpotential of 80 mV to produce CO. The enhanced catalytic performance is mainly attributed to the high surface density of Mn-N4 sites, abundant defects, and high electrochemical active surface area. This work provides the possibility to improve the CO2 electroreduction performance of inert catalysts through surface structure design.

Stabilizing Metal Coating on Flexible Devices by Ultrathin Protein Nanofilms.

The significant modulus difference between a metal coating and a polymer substrate leads to interface mismatches, seriously affecting the stability of flexible devices. Therefore, enhancing the adhesion stability of a metal layer on an inert polymer substrate to prevent delamination becomes a key challenge. Herein, an ultrathin protein nanofilm (UPN), synthesized by disulfide-bond-reducing protein aggregation, is proposed as a strong adhesive layer to enhance adhesion between polymer substrate and metal coating. Unlike traditional biopolymer adhesives with micrometer-scale thicknesses, the UPN layer is minimized to nanometer/single-molecular scale. Such UPN thereby effectively enhances the interfacial adhesive strength and reduces the cohesion contribution in the entire adhesion system by directly connecting two interfaces with a nearly single-molecular thickness. Using UPN as the adhesive layer, a multifunctional metal coating could be reliably adhered on flexible polymer substrates by ion sputtering, delivering unprecedented adhesion stability even under repetitive mechanical deformation. Applications of this design include reversible transparency control, tension-responsive encryption, reusable optical sensing, and wearable capacitive touch sensors. This work highlights UPN's potential to create strong bonding strength between flexible polymers and metal coatings, offering a biocompatible solution with high surface activity and low cohesion, facilitating the development of hybrid devices with stable metal nano-coating.

Size-dependent Copper Nanoparticles Supported on Carbon Nanotubes with Balanced Cu+ and Cu0 Dual Sites for the Selective Hydrogenation of Ethylene Carbonate.

Cyclic carbonate hydrogenation offers an alternative for the efficient indirect CO2 utilization. In this study, a series of carbon nanotubes (CNTs) supported xCu/CNTs catalysts with different Cu loadings were fabricated using a convenient impregnation method, and exhibited excellent catalytic activity for the hydrogenation of ethylene carbonate to methanol and ethylene glycol. The structural and physicochemical properties revealed that acid treatment of CNTs resulted in plentiful oxygen-containing functional groups, providing sufficient anchoring sites for copper species. The calcination process conducted under an inert atmosphere resulted in the formation of ternary CuO, Cu2O, and Cu composites, enhancing the metal-support interaction and facilitating the formation of balanced Cu0 and Cu+ dual sites as well as high active surface area after reduction. Contributed to the synergetic effect of balanced Cu+ and Cu0 species proved by density functional theory calculation and the electron-rich CNTs surface, the 40Cu/CNTs catalyst achieved strengthened catalytic performance with methanol yield of 83%, ethylene glycol yield of 99% at ethylene carbonate conversion of >99%, and 150 h of long-term running stability. Consequently, CNTs supported Cu serve as efficient non-silica based catalyst for ester hydrogenation.

The application of semiconductor nanomaterials in renewable energy

Abstract. In the development of renewable energy, the usage of solar cells, fuel cells, hydrogen energy, thermoelectric energy, and thermal energy has become a significant focus of research and development. Semiconductor nanomaterials play important roles in these fields. This paper focuses on the usage of TiO2 and In2O3 in renewable energy and finds out the trends and outlook of semiconductor nanomaterials in this field. TiO2 nanomaterials have attracted widespread attention due to their unique structure and excellent properties, such as their large specific surface area, high surface activity, and sensitivity. TiO2 nanomaterials are highly active in photovoltaic applications and play an important role in the search for renewable, clean energy technologies. In2O3 is an excellent n-type transparent semiconductor functional material, characterized by high sensitivity, low resistivity, good conductivity, high catalytic activity, and wide bandgap width. It has shown good competitiveness in gas sensors, solar cells, and photocatalysis fields. Although these semiconductor nanomaterials have many advantages, there are still some drawbacks that hinder their development. There is still much work to be done for the wider application of semiconductor nanomaterials in the field of renewable energy.

“Nanoregion” effect of ionic liquid mixture system for preparing highly active porous electrocatalytic hydrogen production materials

The development of porous electrocatalytic materials with high activity and large specific surface area is the key to realizing efficient hydrogen production by water electrolysis. In this paper, a universial strategy for preparing porous non-precious metal electrocatalysts with high effective surface area is provided based on the “nanoregion” formed by ionic liquid mixture system, and the feasibility is verified by constructing a porous NiCo@NC based electrocatalyst. The microstructure, surface composition, specific surface area and electrochemical properties of the porous electrocatalyst are investigated systematically. Compared with the traditional hydrothermal synthesis, the “nanoregion” effect can give the NiCo@NC electrocatalyst rich pore structure and good hydrophilicity, thus effectively improve the effective surface area available for the electrochemical reaction. As a result, the overpotential for HER on NiCo@NC-500 prepared in the ionic liquid mixing system is 113 mV lower than that on NiCo@NC-500-w prepared by common hydrothermal process, and the Tafel slope decreases by 37 mV dec−1 (33.9 %), further verifying the effectiveness of this simple and green strategy to develop porous non-precious metal electrocatalysts for hydrogen production by the “nanoregion” effect of ionic liquid mixture system.

Scientific Insights into the Quantum Dots (QDs)-Based Electrochemical Sensors for State-of-the-Art Applications.

Size-dependent optical and electronic properties are unique characteristics of quantum dots (QDs). A significant advantage is the quantum confinement effect that allows their precise tuning to achieve required characteristics and behavior for the targeted applications. Regarding the aforementioned factors, QDs-based sensors have exhibited dramatic potential for the diverse and advanced applications. For example, QDs-based devices have been potentially utilized for bioimaging, drug delivery, cancer therapy, and environmental remediation. In recent years, use of QDs-based electrochemical sensors have been further extended in other areas like gas sensing, metal ion detection, monitoring of organic pollutants, and detection of radioactive isotopes. Objective of this study is to rationalize the QDs-based electrochemical sensors for state-of-the-art applications. This review article comprehensively illustrates the importance of aforementioned devices along with sources from which QDs devices have been formulated and fabricated. Other distinct features of QDs devices are associated with their extremely high active surfaces, inherent ability of reproducibility, sensitivity, and selectivity for the targeted analyte detection. In this review, major categories of QD materials along with justification of their key roles in electrochemical devices have been demonstrated and discussed. All categories have been evaluated with special emphasis on the advantages and drawbacks/challenges associated with QD materials. However, in the interests of readers and researchers, recent improvements also have been included and discussed. On the evaluation, it has been concluded that despite significant challenges, QDs-based electrochemical sensors exhibit excellent performances for state-of-the-art and targeted applications.

Surface and aggregation behavior of butynediol tetraethoxylate-based trisiloxanes

Butynediol ethoxylate-based siloxane surfactants have attracted considerable attention owing to their low foam content and strong wetting power. In this study, butynediol tetraethoxylate-based trisiloxane (TBEO-2) with a longer hydrophilic chain than that of butynediol diethoxytrisiloxane surfactant (TBEO-1) was designed and prepared by the hydrosilylation reaction, and the molecular structure of the product was analyzed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR and 29Si NMR) and its surface and aggregation behaviors were investigated using a range of techniques. The results showed that TBEO-2 exhibits a high surface activity, strong aggregation capacity, low foam content, strong wettability, and good water solubility. Therefore, butynediol tetraethoxylate-based trisiloxane can be considered an ideal low-foam wetting agent for use in various applications.

Overcoming volumetric capacitance-rate performance tradeoff with 0D/2D conductive carbon nitride/phosphorene heterostructure for flexible supercapacitor

Few-layer black phosphorus (FL-BP) is considered a rising star 2D material for flexible supercapacitors (FSCs) due to its exceptional properties, including mechanical flexibility and high active surface area. However, the disordered deposition of FL-BP nanoflakes often leads to face-to-face restacking, which diminishes the effective active area and ion transport channels. This poses a huge challenge in simultaneously achieving high volumetric capacitance and rate capability. To address this, a 3D porous 0D/2D FL-BP/conductive carbon nitride (FL-BP/c-CN) film has been developed. The introduction of 0D c-CN nanoparticles effectively prevents the restacking of FL-BP nanoflakes and expands the nanofluidic channels, thus facilitating charge transport and ions diffusion. Additionally, the highly conductive c-CN nanoparticles embedded into the FL-BP layers significantly improve overall conductivity. As a result, the FL-BP/c-CN film-based FSC demonstrates a remarkable rate performance, retaining 70% capacitance as the scan rate increases from 10 to 100 mV/s. Moreover, the incorporation of 0D c-CN nanoparticles increases the available space for charge accumulation, yielding a volumetric capacitance of 28.5 F/cm3 at a scan rate of 10 mV/s, which is three times higher than that of a pure FL-BP film electrode (9.2 F/cm3). This work presents an innovative approach for developing high-performance FL-BP-based FSCs.

Development of an efficient bifunctional electrocatalyst based on Co/CoSe2 nanoparticles embedded in N, Se co-doped carbon for AEMFC and rechargeable Zn-air battery

We suggest a hollow-structured N, Se dual-doped carbon framework embedded with Co/CoSe2 nanoparticles (Co/CoSe2@NSeC) as highly efficient bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The prepared electrocatalyst exhibits high electrochemical active surface area attributed to its unique hollow/porous structure and defective heteroatom doping sites. Furthermore, the strongly coupled heterojunction between Co and CoSe2 species not only provides abundant and highly active sites but also generates built-in electric field, thereby promoting electron transfer during the electrocatalytic reaction. Based on the above considerations, the prepared catalyst shows excellent bifunctional electrocatalytic performance. Leveraging the excellent ORR activity of Co/CoSe2@NSeC, alkaline exchange membrane fuel cells (AEMFC) with the Co/CoSe2@NSeC as air cathode exhibits high power density of 171.23 mW cm2. Furthermore, the rechargeable Zn-air battery employing the Co/CoSe2@NSeC shows high specific capacity (729.4 mAh gZn−1), peak power density (192.88 mW cm2), and sustained stability over 300 cycles.

Dual modification of cobalt silicate nanobelts by Co3O4 nanoparticles and phosphorization boosting oxygen evolution reaction properties

Oxygen evolution reaction (OER) process is the “bottleneck” of water splitting, and the low-cost and high-efficient OER catalysts are of great importance and attractive but they are still challenging. Herein, a dual modification strategy is developed to tune and enrich the structure of cobalt silicate (Co2SiO4) showing boosted OER properties. Cobalt oxide (Co3O4) decorated Co2SiO4 nanobelts, denoted as CS, is firstly prepared using a Co-based precursor by a facile hydrothermal reaction. Then, cobalt phosphide (CoP) nanoparticles are in-situ grown on CS (denoted as CS-P) by the phosphorization process, which provide many active sites and boost the surface reactivity. The experimental results and density function theory (DFT) calculations both reveal that the CoP on CS can improve the conductivity and ensure fast kinetics, thus leading to boost the OER properties of Co2SiO4. When the phosphorization temperature is at 400 °C (CS-P400), it gains the lowest overpotential of 297 mV, which is much lower than CS (340 mV) and Co2SiO4 (409 mV) at 10 mA·cm−2, and even superior to the state-of-the-art transition metal silicates. CS-P400 also achieves high electrochemical active surface area (ECSA) and small Tafel slope owing to its porous structures with large specific surface area and nanosheet-like structures which are good for exposing many active sites and favorable to the fast kinetics. This work not only provides a dual modification route to boost catalytic activity of Co2SiO4 (CS-P400), but also sheds light on a new avenue for developing highly dispersed CoP on silicates to boost OER performances.

Advanced (Cu,Co)Se2 Nanocubes and Ti‐MXene Based Screen Printed Electrodes for High Performance Flexible Microsupercapacitors

AbstractNowadays, the demand for portable micro‐energy storage devices with high energy density and scalable printing with cost‐effective fabrication for microsupercapacitors (MSC) are essential. Furthermore, the urgent need for this high‐performance MSC to meet all industrial sector requirements are very challenging. Herein, the screen printable MSC with high energy density is demonstrated by using copper hexacyanocobaltate (CuHCCo) derived (Cu,Co)Se2 nanocubes as the positive electrode and Ti‐MXene (Ti3C2Tx) as the negative electrode. The prepared battery type (Cu,Co)Se2 nanocubes greatly enhance the high electrochemical activity and active surface area. As a result, it delivers a high specific capacity of 602 C g−1 at the current density of 1 A g−1. The fabricated screen printable asymmetric MSC has enhanced ion‐to‐electron transfer in printable microelectrodes with numerous electrochemical active sites and delivered the high areal capacitance of 58 mA cm−2 at the current density of 1 mA cm−2 with a wide potential window. The device gives a high energy density of 8.06 µWh cm−2 and a high power density of 5 mW cm−2. These results demonstrate the new strategies of fabricating electrode materials in screen printable asymmetric MSC and show promising in microscale energy storage devices in the miniaturized devices with sustainable self‐powered compatibility.

Preparation of porous (Mo2/3Y1/3)2AlC and its hydrogen evolution reaction performance

Porous (Mo2/3Y1/3)2AlC MAX phase ceramic was prepared by reaction sintering method using Mo, Y, Al, and graphite powder as raw materials. The influence of changes in Al content on the purity of the obtained samples was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, and bubble point method. The conditions for obtaining a pure phase were identified, and the transformation path of the phase during sintering and the mechanism of pore formation were provided. The linear sweep voltammetry (LSV) cure and cyclic voltammetry (CV) cure of MAX were tested using an electrochemical workstation. It can be calculated that MAX exhibits good hydrogen evolution reaction (HER) performance under alkaline conditions due to its high electrochemical active surface area (ECSA) of 373.2 and small Tafel slope of 41.7 ​mV·dec−1.

Oxidation-induced graded bandgap narrowing in Two-dimensional tin sulfide for high-sensitivity broadband photodetection

Two-dimensional (2D) layered group-IV monochalcogenides with large surface-to-volume ratio and high surface activity make that their structural and optoelectronic properties are sensitive to air oxidation. Here, we report the utilization of oxidation-induced gradient doping to modulate electronic structures and optoelectronic properties of 2D group-IV monochalcogenides by using SnS nanoplates grown by physical vapor deposition as a model system. By a precise control of oxidation time and temperature, the structural transition from SnS to SnSOx could be driven by the layer-by-layer oxygen doping and intercalation. The resulting SnSOx with a graded narrowing bandgap exhibits the enhanced optical absorption and photocurrent, leading to the fabricated SnSOx photodetector with remarkable photoresponsivity and fast response speed (<64 μs) at a broadband spectrum range of 520–1550 nm. The peak responsivity (7294 A/W) and detectivity (9.54 × 109 Jones) of SnSOx device are at least two orders of magnitude larger than those of SnS photodetector. Moreover, its photodetection performance can be competed with state-of-the-art of 2D materials-based photodetectors. This work suggests that the air oxidation could be utilized as an efficient strategy to engineer the electronic and optical properties of SnS and other 2D group-IV monochalcogenides for the development of high-performance broadband photodetectors.

Evaluation of Biosurfactants to Preflush for Offshore Wells.

With the improvement of environmental protection requirements in offshore oil and gas exploration, there is a great demand to find environmentally friendly surfactants for cementing preflush fluids. In the present paper, the application potential of three biosurfactants of rhamnolipid, lipopeptide, and sophorolipid in the preflush fluid was evaluated through a series of experiments. The experiments studied the interfacial tension (IFT) of the biosurfactants, resistance to temperature, salt resistance (sodium chloride and sea salt), and the influences of the studied biosurfactants on the rheological compatibility and capabilities to convert the wettability of the formation from oil-wet to water-wet, mud cake removal efficiency, and to improve the interfacial bonding properties of the preflush fluid. The results showed that rhamnolipid, lipopeptide, and sophorolipid exhibited excellent surface activities in high-temperature and sodium chloride (NaCl) environments. When exposed to sea salt, lipopeptides lost their function due to agglomeration, while rhamnolipids and sophorolipids maintained structural stabilities and high surface activities. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the combined biosurfactant had the best surface activity among the studied surfactants. The combined biosurfactant not only had good rheological compatibility with the drilling fluid and cement slurry but also showed excellent properties in the removal of mud cake. In addition, the effect of the removal of the mud cake was verified by the gas channeling experiment. The experimental results show that the presence of mud cake can reduce the bonding strength. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the removal efficiency of mud cake was the highest, and the interfacial bonding property of the cement sheath can be improved.

Sorbents Based on Natural Zeolites for Carbon Dioxide Capture and Removal of Heavy Metals from Wastewater: Current Progress and Future Opportunities

This review is dedicated to the potential use of natural zeolites for wastewater treatment and carbon dioxide capture. Zeolites, due to their microporous structure and high surface activity, are used as sorbents. One effective application of zeolites is in wastewater treatment, which leads to the removal of pollutants and improvement in water quality. Zeolites can also be used for carbon dioxide capture, which helps reduce its concentration in the atmosphere and addresses climate change issues. This review examines recent research on the use of natural zeolites for the removal of heavy metals from water and CO2 capture. It explores the broad applications of natural zeolites by understanding their adsorption capabilities and the mechanisms affecting their performance in water purification from heavy metals and CO2 capture.